Improvement in jig-saws



G. W. CARY.

Jig-Saw.

No. 212,355. Patented Feb. 18, 1879 INVENTORI WITNESSES;

UNITED STATES PATENT OFFICE.

GEORGE W. CARY, OF PROVIDENCE, RHODE ISLAND.

IMPROVEMENT IN JlG-SAWS.

Specification forming part of Letters Patent No. 212,355, dated February 18, 1879; application filed November 21, 1878.

To all whom it may concern:

Be it known that I, GEORGE W. CARY, of the city and county of Providence and State of Rhode Island, have invented a new and useful Improvement in Jig-Saws; and I here by declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification.

Figure 1 is a view of my improved jig or fret saw, shown as secured to a table. It is shown partly in section, so as to show the cocentric or pitman connection with the saw more clearly. Fig. 2 is an end view of the.

driving mechanism, parts of which are shown in section. Fig. 3 is a view of the rollingclutch, by which the driving power is connected with and disconnected from the driving-shaft.

The invention consists in the peculiar and novel manner of driving the saw from a continuously-revolving shaft when the said shaft is driven by a foot-treadle at a greater speed than the treadle, as will be more fully set forth hereinafter, and more particularly pointed out in the claims.

In the drawings, A is a metal frame, arranged to set on a table, and provided with a clamping-arm, in which the clamp-screw B is secured, so that the whole maybe readily secured to a table, bench, or similar support. C is a projecting arm, to which the driving mechanism, the vertical slide, and adjustable table are secured. D is a curved arm, to which the slotted guide E is secured, and within which the reciprocating cross-head or slide 6 moves. This cross-head c is provided with a pin or equivalent projection resting on the curved spring 0, and when the saw is secured and in operation the spring a secures a tension on the saw, drawing the same upward against the crank or eccentric, so that the saw is not liable to be bent or broken. F is a hinged adjustable table. 9 is an eccentriccrank, connected with the guide to which the lower end of the saw is secured. The eccentrio-crank g is driven by the main drivingshaft, on one end of which the flywheel h is secured, and on the other end the clutch This clutch i is shown in view in Fig. 3, and

may form a part of the fly-wheel, so that the wheel It may be dispensed with. j is a fixed spindle, in the end of which the driving-shaft has a stepbearin g. On the spindle j the drum k revolves, being limited in its revolution by the helically-coiled spring 70, one end of which is secured to the stationary spindle j and the other to the drum 7c. The strap L is wound around the drum 7c in the groove Z and connected with the treadle. the treadle is moved down, the drum 70 will revolve on the spindle in the direction in which the strap Z will unwind from the drum, and as the coiled spring is wound in the drum 7c in the opposite direction the tension on the spring It? will be increased, and when the treadle makes its upward motion the spring 70 will turn the drum is in the opposite direction, and will rewind the strap Z into the groove 1, so that an alternate rotary motion in an opposite direction will be imparted to the drum k.

The face m of the drum 7c fits closely to the disk 6, and a projecting rim, or, is placed on the disk c, and on the face on of the drum a curved incline, 0, is secured, (shown in section in Fig. 3,) between which and the rim n the roll 1) is placed.

Fig. 3 shows the roll 1) in contact with the rim n of the disk t', and also in contact with the inclined curved piece secured to the drum is, in solid lines, and out of contact with the rim n in broken lines, thus forming a clutch-connection in one direction, and releasing the same by the rolling of the roller p in the other direction, the momentum of the flywheel compensating for the time when the strap is rewound, and driving the saw, so that a continuous rotary motion is imparted to the drivingshaft from the reciprocating treadle, and im parting motion to the saw, but many times the number of reciprocations of the treadle.

A saw is thus made to move at ahigh speed, and fret-work can be executed with great accuracy and rapidity.

The whole driving mechanism may be inclosed in a suitable case and protected from dust and injury.

The construction of the frame is sim ple and strong. The spring 6 can be made adjustable When, therefore,

by placing a screw against the heel of the 2. The combination, with the saw, the eccentric-crank g, and a disk or fly-Wheel, of a clutch consisting of the curved incline 0 rim n, and roller 19, the spring 70, and strap 1, and the adjustable spring 0, substantially as and for the purpose set forth.

GEORGE W. GARY.

Witnesses JOSEPH A. MiLLER, J OSEPH A. MILLER, Jr. 

